Abstract: The present invention is generally directed toward a mobile device that can be used in a secure access system. More specifically, the mobile device can have credential data loaded thereon remotely updated, enabled, disabled, revoked, or otherwise altered with a message sent from, for example, a control panel and/or controller in the system.

Abstract: A card retention assembly includes a shield and a retraction mechanism. The shield is essentially non-transmissive of radio frequency signals and encloses a card receptacle which retains an RFID card when the retraction mechanism is in a retracted position. The retraction mechanism includes a spool and a retention line connectable to the RFID card and connected to the spool. Manually withdrawing the RFID card from the card receptacle causes the retention line to unwind from the spool and transitions the retraction mechanism from the retracted position to an extended position. The retraction mechanism is biased to the retracted position causing the retention line to wind back onto the spool and automatically returning the RFID card back to the card receptacle when the RFID card is manually released. Radio frequency communication between the RFID card and a proximal card reader is prevented when the RFID card is within the card receptacle and is permitted when the RFID card is outside the card receptacle.

Abstract: A card retention assembly includes a shield and a retraction mechanism. The shield is essentially non-transmissive of radio frequency signals and encloses a card receptacle which retains an RFID card when the retraction mechanism is in a retracted position. The retraction mechanism includes a spool and a retention line connectable to the RFID card and connected to the spool. Manually withdrawing the RFID card from the card receptacle causes the retention line to unwind from the spool and transitions the retraction mechanism from the retracted position to an extended position. The retraction mechanism is biased to the retracted position causing the retention line to wind back onto the spool and automatically returning the RFID card back to the card receptacle when the RFID card is manually released. Radio frequency communication between the RFID card and a proximal card reader is prevented when the RFID card is within the card receptacle and is permitted when the RFID card is outside the card receptacle.

Abstract: An electronic anti-shoplifting system monitors articles of merchandise in a sales outlet to deter shoplifting. The system is provided with transponder tags connected to the articles of merchandise. A tag exciter is positioned at an exit leading from the sales outlet and generates an RF surveillance excitation signal. If a customer carries an article through the exit without removal authorization due to failure to pay for the article, the transponder tag is activated, being powered by the RF surveillance excitation signal as the customer passes the tag exciter. The activated transponder tag generates an RF surveillance response signal that triggers an alarm. If the customer has removal authorization as the result of paying for the article, the transponder tag is reprogrammed to modify the operational data stored therein.

Abstract: A wireless modem employs a radio frequency (RF) transponder system components to remotely access the memory of an electrical or electro-mechanical device by providing an exciter/reader/writer (ERW) circuit free of electrical contact with the electrical or electro-mechanical device and a transponder including a transmit/receive antenna, a reading circuit, a programming circuit, and a transponder memory. The transponder memory is directly connected to the device memory. The ERW circuit initially generates an RF excitation signal powering the transponder. In response to the RF excitation signal, the transponder generates a RF response signal using the reading circuit that is transmitted back to the EWR circuit. The RF response signal includes data from the device memory. The RF response signal is received by the ERW circuit, which in turn generates an RF write signal that is transmitted to the transponder.

Abstract: An RF identification system for generating data indicative of an item that is tagged, and one bit of variable data representative of an external stimulus. An ID code reader is provided and an RF identification tag is coupled to the item that is to be monitored and the ID code reader queries the tag. The tag comprises two RF transponder chips that store a data relating to the item, and an excitation coil coupled thereto. A switch is coupled to the chips and excitation coil, and a capacitor is coupled across the switch. A sensor is coupled to the switch for generating one bit of variable data representative of an external stimulus, such as the pressure in a tire. The ID code reader comprises an exciter and RF excitation coil, and a receiver and an RF receiver coil. The receiver includes phase detection circuitry for detecting a state of the switch by detecting the phase shift between signals received from each of the transponder chips. When the switch is shorted, the effect of the capacitor is nullified.

Abstract: An RF transponder system is provided that is capable of detecting and correcting data transmission errors. The RF transponder system includes an exciter that generates an RF excitation signal and a transponder that receives the RF excitation signal and is powered thereby. The transponder generates and transmits a RF response signal including a plurality of data sets each containing a common message. At least one of the data sets is encoded in a manner different from the remaining data sets. The RF response signal is received by a reader that decodes the encoded data sets. Corresponding bits of each of the data sets are compared for purposes of error detection. If a majority of corresponding bits from each of the data sets match, a valid bit is defined thereby. Bits that are not in the majority are discarded. An invalid bit is defined where less than a majority of corresponding bits match a selected bit of a selected data set.

Abstract: An RF transponder transmits information on the distance traveled by a wheeled vehicle in response to an interrogation signal from an exciter/receiver. A rotation sensor, preferably an odometer/shaft encoder combination that is mounted on a vehicle wheel, provides to the transponder a signal which indicates the distance traveled by the vehicle; the transponder is also preferably mounted to the wheel's rotational hub. The transponder preferably includes a memory with a reprogrammable portion that stores the sensor information, and a non-reprogrammable portion that stores an identification code, all of which is read out in response to an interrogation signal. Driving distances can be obtained automatically without having to read the vehicle's dash board odometer.

Abstract: A tire transponder system seats a transponder coil in a flexible resilient tube that is positioned around a vehicle wheel. The transponder antenna is lodged in a groove that extends around the tube, and responds to an excitation signal by transmitting a signal that contains identification information and/or information on the tire condition. For tire condition information, a diode is connected in circuit with the transponder coil to double the frequency of the signal returned by the transponder. A switch that is connected to bypass the diode is operated by a tire condition sensor, such as a pressure sensor, when the sensed condition crosses a threshold level in a predetermined direction. The change in the frequency of the transponder's returned signal when the threshold has been crossed is used to activate a response such as a low tire pressure alarm.

Abstract: A particulate, resilient, electrically conductive member having a low thermal mass extends across the width of a conductive-backed recording paper and conducts electrical energy to the conductive backing to heat the paper and develop an image.The member comprises a plurality of closely spaced resilient fingers which extend across the width of the web. A curved crown on each of the fingers protrudes through a slot in a plate over which the paper passes. The ends of the fingers are restrained by the slot so that they are not readily susceptible to damage.

Abstract: The beam of a line scan fiber optics cathode ray tube is intensity modulated and is repeatedly swept along the fiber optics strip of the tube by a horizontal deflection coil to place on a transversely moving record sheet recorded gray scale images which are representative of received data signals. A sheet velocity sensor, a frequency to voltage converter, and a differentiator produce a voltage signal proportional to short term sheet velocity errors, and an integrator converts that signal into a signal which represents the time integral of each of such errors. The integral signal controls a vertical deflection coil for the tube so that each of the sheet velocity errors is accompanied by a movement of the cathode ray tube beam in the vertical direction, and hence along the path of sheet travel. This vertical beam movement maintains the instantaneous relative velocity between the sheet and the beam substantially constant notwithstanding the short term sheet velocity errors.

Abstract: A display apparatus is provided whereby a constant intensity of record is obtained notwithstanding substantial changes in the linear speed of the record member. The cathode ray sweep frequency is maintained at a constant rate commensurate with the highest speed of the record member. As the speed of the record member is reduced by a given factor, the number of scans of the cathode ray beam which are unblanked are reduced by the same factor.

Abstract: A vector CRT display apparatus for faithfully reproducing an analog signal having high frequency components include an A-D converter, a digital minimum/maximum circuit and a recirculating shift register to derive from the signal, in successive sampling periods, two digital words representing, respectively, a minimum amplitude value date point and a maximum amplitude value data point of the signal. In each sampling period, the minimum/maximum circuit stores in the memory the most relevant of the minimum and maximum amplitude values and determine whether the remaining values should be held over to the next sampling period before it is stored, or can be discarded. As a result, if new minimum and new maximum amplitude values occur in the same sample period, one will be loaded into the memory and the other will be held over and loaded into the memory in the next sample period.

Abstract: An improved X-Y or vector type cathode ray tube circuit includes means to sense the imminence of and to inhibit excessive concentrations of electron beam current during the plotting of X-Y loops, which concentrations produce spots or points on the cathode ray tube screen that are essentially repetitive and convey no useful information to the observer, and if allowed to persist, tend to burn the phosphor coating of said screen.

Abstract: The minimum and maximum values attained by an analog data signal in each of successive sampling periods are determined by alternately operative amplitude detectors which produce and store a corresponding minimum and maximum signal for each of these periods. A generator produces a ramp signal which repeats in each period in synchronism with the sweep of the beam of a fiber optics strip cathode ray tube along the strip thereof. A record sheet is advanced at right angles to this strip. Comparators are operative in each period to compare the stored detector signals of the immediately preceding period with the ramp signal, and to produce an output when the ramp signal exceeds either of the detector signals. An EXCLUSIVE OR gate receives these outputs and unblanks the normally blanked tube beam for a time in each period to produce a line on the sheet extending along the strip between points representing the minimum and maximum signal values for the preceding period.